DE1122362B - Process for the production of paper stock for printing and packaging papers from hemp - Google Patents

Description

It is known that certain papers, such as printing paper and newsprint, are composed of one Mixture of long fibers, which play the role of reinforcing the leaf, and short fibers, which serve as pure fillers to give the sheet the property of softness and that necessary for printing To give permeability. In order to produce these papers, one uses in the technique a Mixture of paper stocks made from hard-boiled softwood with long fibers at low yield and mechanically obtained paper stocks with short fibers that are produced in high yield from light wood obtained by grinding.

On the other hand, it is known that it is used for the manufacture of certain packaging papers, in particular bags for cement and similar substances, it is expedient to produce a paper stock that has as high a proportion as possible contains long fibers in order to give the paper a high degree of strength, while it is sufficiently strong Retains porosity that allows air to escape. It is also used chemically recovered paper stocks, with long fibers treated to give permeable papers.

Various processes are known to make the paper materials used in the paper industry from wood to be replaced by substances from annual plants.

According to a known method, leaves, twigs and other green parts of the plant are cold Water crushed to a length of about 3 to 6 cm, by washing out staining parts, such as chlorophyll and some other substances that interfere with the chemical treatment. That obtained product can be compressed, transported and chemically digested with lye or other means will.

Another method is used to boil green parts of plants several times at about 110 ^° C. in pure water, ferment the sugar solution obtained to alcohol and boil the washed product under pressure with a lye containing alkali metal sulfite, alkali metal carbonate and some alkali metal hydroxide. The latter dissolves the chlorophyll or its conversion products. Textile fibers or cellulose are obtained in this way. The latter process gives more complete and better results than the former, but nevertheless with hemp and similar textile fibers the paper stocks obtained are not sufficiently white to be used without an expensive bleaching treatment.

The use of hemp in paper manufacture, namely the long fiber for fiber paper and the short fiber for printing and writing paper is a process for producing it

of paper stocks for printing

and packaging papers made from hemp

Applicant:

Eugene Gilbert Voiret,
Lyon, Rhone (France)

Representative: Dipl.-Ing. W. Meissner, Berlin-Grunewald, and Dipl.-Ing. H. Tischer, Munich 2, Tal 71,

Patent attorneys

Claimed priority:
France of November 8, 1956 (No. 36 875)

Eugene Gilbert Voiret,

Lyon, Rhone (France),

has been named as the inventor

also known. It is also known to wash out the digested mass with flowing water; when breaking up straw with sulphites, yields of around 70% have already been achieved.

The invention makes it possible, starting from hemp and other similar textile plants, paper stock to produce with high yield, without special bleaching for the production of common printing paper and packaging paper is sufficiently white.

According to the invention, paper stocks for printing and packaging paper are made from hemp, with the method is characterized by the combination of features known per se, which consist in that one crushes the raw material into pieces of at most 5 to 10 mm, then a mild one Digestion with sodium sulfite solution at such temperatures and times is subject to a yield from 70 to 85%, then the chlorophyll is removed with flowing water and finally the Mass mechanically frayed. The one to be digested can be used in the same way before or after the lye treatment Additionally crush the material by impact and then some of the lignin substances split off.

According to one variant of the method, the substance obtained can be converted into a

109 760/143

A proportion with longer fibers and a proportion with shorter fibers can be sorted.

example 1

The remaining hemp leaves are removed by threshing or with the help of metal brushes, then cut up the hemp in fragments of 10 mm and treated with lye IV2 for up to 2 hours a temperature of 125 to 140 ° C in a 2 to 3% sodium sulfite solution in an amount of 7 to 81 lye per kilogram of material. When the lye treatment is finished, the material treated with lye is mixed in flowing water until the greenish pigments disappear, then one proceeds to defibration. Yield about 75%.

Example 2

Hemp, treated as in Example 1 and cut, is in vacuo and under pressure with a 4 to 6% sodium sulfite solution treated. The mass is allowed to drain and cooked directly with steam up to 2 hours at a temperature of 130 to 140 ° C or even better for a 1/2 hour at a temperature of 155 ° C. The mass treated in this way is mixed with flowing water and then, as in the previous example, defibrated. Yield about 75%.

The paper stocks obtained according to the exemplary embodiments are sorted in the customary manner. Man uses the long fibers to make Kraft paper, while the separated short fibers used as a filler in the manufacture of book or newsprint.

Claims (3)

PATENT CLAIMS: 1. Process for the production of paper stocks for printing and packaging paper from hemp, characterized by the combination of the following individual characteristics, known per se, which consist of that one crushes the raw material into pieces of at most 5 to 10 mm, then one subject to mild digestion with sodium sulfite solution at temperatures and times such that a yield of 70 to 85% results, then the chlorophyll is removed with flowing water and finally the fabric is mechanically frayed. 2. The method according to claim 1, characterized in that the material to be digested before or after the lye treatment, additionally crushed by the impact effect and then incorporated ao part of the lignin matter is separated. 3. The method according to claim 1, characterized in that the substance obtained in itself known way into a portion with longer fibers and a portion with shorter fibers. »5 is animalized. Considered publications:
German Patent Nos. 388998, 524298;
British Patent Nos. 4,984 of 1880, 216,533, 699 232, 707,982; Wochenblatt für Papierfabrikation, born in 1956, pp. 278 and 279.